(1) Field of the Invention:
The invention relates to a welding wire container, and more particularly to a welding wire packaging container of the type which accommodates a welding wire winding with a multitude of looped wire layers of cylindrical or hollow tubular form and which permits smooth wire withdrawal without disturbing or being entangling with other looped layers of the wire.
(2) Description of Prior Art:
In the field of automatic or semi-automatic welding, there is a trend toward larger packages with a larger stock of welding wire to thereby reduce the time required for wire replacement. Therefore, there is an increasing demand for pail type containers which are easily adapted to larger capacities. When withdrawing welding wire from such a container, it is necessary to ensure that the wire be withdrawn smoothly without disturbing or being entwined with other looped layers of the wire.
The wire which is accommodated in the cylindrical container (hereinafter referred to as pail container) is in the form of a winding having multiple layers of wire loops with inner diameters smaller than that of the container. Due to the rigidity of the wire itself, the looped layers are continuously under the influence of a force which tends to widen the diameter of loops or convolutions. However, as wire is withdrawn from the container, the loosened wire portion tends to spring back and disturb or become entangled with other looped layers or with itself, causing variations in the resistance of wire withdrawal. In such cases, it becomes difficult to withdraw the wire or to feed the wire smoothly. In the conventional pail container wire package, each loop of the coil is imparted with one twist per loop or convolution when packaging the wire in order to prevent torsional deformation of the wire which is being withdrawn axially from the unrotated container. Consequently, the packaged wire tends to spring up with a greater force. Therefore, as shown in FIG. 1, a conventional pail container is constructed with double cylinders, winding a wire 3 in multiple layers between an outer cylinder 1 and an inner cylinder 2 to thereby prevent disintegration of the wire 3, and retaining members 4 are placed on the overlying convolutions of the wire which would otherwise tend to spring up. The inner cylinder 2 is provided with a guide member 6 at the upper end thereof to ensure smooth withdrawal of the wire.
However, such containers involve a large resistance to wire withdrawal since the wire portion which is withdrawn from the container is frictionally contacted with at least the edge portion 4a on the inner surface of the retaining member 4, the outer periphery of the inner cylinder 2 and the guide member 6. In addition, the bending force which acts on the respective contacting portions imparts irregular complicated torsional deformations to the withdrawn wire portion, necessitating a number of rectifying rolls. Further, the containers of this sort entail problems in that the inner cylinder hinders to and complicates the wire winding and packaging operation, and the construction of the container itself, which requires a large number of internal parts, is complicated and costly. Besides, since the inner cylinder has the same height as the outer cylinder, it is necessary to provide the guide hole of a wire withdrawing device at a level at least 200 mm higher than the upper lid surface of the package.
Other welding wire withdrawing methods and packages are disclosed, for example, in Japanese Laid-Open Utility Model Application No. 55-143986, Japanese Laid-Open Patent Application Nos. 55-145971 and 55-145972, and Japanese Laid-Open Utility Model Application Nos. 56-6579 and 56-56783.